Anti-fingerprint coating is a technology for specially treating a surface of a substrate such as glass to prevent a contaminant such as a fingerprint from being attached to the surface and easily remove the contaminant even when the contaminant is attached to the surface, and is a surface treatment technology of applying a water-repellent and oil-repellent function of a thin film to a surface.
An externally exposed portion of various home appliances, that is, a window or a case of home appliances such as a mobile phone, a digital versatile disc, etc. has a portion exposed to a hand of a person, and a handprint (fingerprint) is frequently left on a clean surface thereof.
In particular, a smartphone or a tablet personal computer (PC) uses a window as input means, and thus fingerprint resistance is essential for a surface of the window.
Coding schemes has been developed for a coating for preventing a fingerprint from leaving on glass or plastic, and the coding schemes use technologies such as vacuum coating, dip coating, spray coating, etc. according to application fields thereof. A vacuum deposition technology using an electric beam which is mainly used to deposit a dielectric substance on a glass lens has been domestically developed.
The vacuum deposition technology is a technology for evaporating a fluorine compound in a vacuum to coat glass or plastic with a thin film made of the fluorine compound. In this technology, while a defective rate of a surface due to contaminants is low, there is a problem of low productivity due to a batch process. Even though large equipment has been developed to solve the problem, a high equipment investment cost has been a problem.
In liquid coating such as dip coating, spray coating, etc., productivity is high due to a continuous process. However, a defective rate is high when compared to vacuum coating, and performance is insufficient.
In addition, in existing deposition for fingerprint resistance, a fluorine compound for lowering surface energy is deposited on SiO2.
When a water-repellent and oil-repellent material is directly deposited on glass or plastic, durability is degraded. Thus, to complement solve this problem, the water-repellent and oil-repellent material is deposited after SiO2 is deposited.
Korean Patent publication No. 10-2011-0138541 relates to a fingerprint resistant thin film structure having excellent durability and a formation method thereof. The fingerprint resistant thin film structure includes a substrate, a grain thin film layer which is formed in a two-dimensional shape on the substrate and includes a plurality of grains and a plurality of grain boundaries, and a fingerprint resistant coating layer which is formed on the grain thin film layer and made of a fingerprint resistant coating material. The fingerprint resistant coating material is formed to penetrate the plurality of grain boundaries to enhance durability of fingerprint resistance, and an undercoating layer is further included between the substrate and the grain thin film layer to enhance adhesive strength of the grain thin film layer, thereby increasing surface roughness of the fingerprint resistant coating layer. In this way, it is possible to prevent the fingerprint resistant coating layer from being easily removed due to abrasion to enhance durability with respect to fingerprint resistance. However, there remain a problem due to a high equipment investment cost, a problem of a high defective rate when compared to vacuum coating, and a problem of insufficient performance.